Early detection of invasive tree pathogens using molecular tools

photo of a researcher monitoring a spore trap next to a body of water

Researcher monitors a wind spore trap

 

Background

Invasive tree pathogens cause immense damage to natural ecosystems and, in turn, significant economic losses. Minnesota’s natural and urban forests have experienced massive ramifications from the introduction of several exotic pathogens—Dutch elm disease and oak wilt, for example.

A recent, newer threat is Heterobasidion Root Disease (HRD, also called annosum root rot) that has the potential to devastate Minnesota’s pines and other conifers. Many pathogens like HRD spread through windborne spores. Oftentimes windborne pathogens are only detected after being established in an area for some time.

New molecular biosurveillance tools can use DNA technology to help detect forest diseases before they establish. Blanchette’s team is developing such molecular biosurveillance tools for a number of priority invasive pathogens to facilitate early detection of tree diseases across Minnesota.

Research questions

  • What is the best way to trap windborne fungal spores for molecular testing?
  • What are the best sampling methods for invasive Phytophthora species?
  • Where are HRD and other invasive tree diseases detected in Minnesota?

Outcomes

Researchers effectively used molecular tools to detect invasive tree pathogens in Minnesota. After collecting and analyzing over 1,500 samples from nurseries, forested areas, waterways, and Christmas tree plantations, they identified 24 different species of Phytophthora. 14 of these species were previously unreported in Minnesota. 

Using several types of spore traps in Minnesota and Wisconsin, they confirmed the presence of HRD, which led to eradication efforts. HRD was found in Wisconsin counties adjacent to Minnesota and several locations in eastern Minnesota. Spore trap types included Burkard, Roto Rod, and windsocks. Wind socks were found to be an effective and inexpensive way to monitor for spores of many species of pathogens.

At the conclusion of this project, researchers recommend continued spore trapping to monitor pathogens as an efficient way to detect pathogens before they become major outbreaks, and to locate the source of pathogens. They also recommend investigating the distribution and completing virulence testing of the Phytophthora species new to the state.

This 4-year research project enhanced statewide efforts to monitor, prevent, and mitigate damage to Minnesota’s natural resources. It also serves as a model of biosurveillance to other states and federal agencies. 

Related research: Biosurveillance of invasive pathogens of woody plants in Minnesota

Publications

Outreach

  • Minnesota Department of Agriculture, 2024
  • The Minnesota Mycological Society, 2024
  • MN DNR - Society of American Foresters Conference, 2024
  • Mahtomedi Garden Club, 2024
  • Presentation at University of Wisconsin-Madison, 2023
  • Presentation at Central Minnesota Christian School, 2023
  • University of Wisconsin-Madison Seminar presentation, 2023
  • CFANS Research Symposium, 2023
  • Plants Get Sick Too, PLPA 1005 - Department of Plant Pathology, 2022
  • University of Minnesota Arboretum presentation, 2022
  • Pikes Peak Mycological Society, 2022
  • North Central Forest Pest Workshop, 2022
  • Upper Midwest Invasive Species Conference, 2022
  • Minnesota Department of Natural Resources Forest Health Workshop, 2022

News and media

Research team

Robert Blanchette | principal investigator

Benjamin Held | co-investigator

Nick Rajtar | PhD candidate

Tessa Kothlow | undergraduate student

Brett Arenz | collaborator

Eric Otto | PhD student

Jennifer Galarneau | undergraduate student

 

Lab or other website

forestpathology.cfans.umn.edu 

 

Collaborating organizations

National Plant Diagnostic Network

Minnesota Department of Agriculture

Minnesota Department of Natural Resources

Minnesota Department of Health

USDA Forest Service